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Farmboy
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Posts:238
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| 03/17/2009 10:04 PM |
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Dennis, We know the house was built 1.5 years ago. What we don't know is what type of construction of the main floor (2x4 or 2x6 studs?), construction of the basement (8" poured concrete or concrete block?), type of insulation in the walls, exterior of the basement walls, in the ceiling, etc.? For a 4 ton unit to heat 3600sf home (includes basement or not?), that home must pretty well built with low infiltration, in other words, tight.
How can a 4 ton ASHP heat a house with a 115,000 Btuh heating load without a lot of help from heat strips? From ClimateMaster charts, heating capacities for a 4 ton Tranquility 27 are 48,300 Btuh (open loop) and 37,500 Btuh (closed loop). That's not even half the calculated load. So the heating strips will have to makeup quite a few Btu's. 115MBH and 48MBH don't sound like the same house. to paraphrase Joe.
Wondering if the A/C seemed to work because you have these 100 ft oak trees shading the house and the system was designed only for the main floor. The basement would normally remain cooler being in contact with the earth and therefore wouldn't need to be air conditioned. So your cooling load could actually have been 4 tons. Was the basement originally finished?
Turning to heating. Again was the basement unfinished and the original ASHP sized to heat the main floor only? Perhaps the ASHP was installed incorrectly or was undersized to begin with, but either way it isn't able to satisfactorily do the job. So, a contractor comes in and calculates 115 kbtuh which is about 9.5 tons. This for the first floor of ___sf and basement of ___sf for a total of ___ sf.
This is an interesting case and we all would like for you to have a successful GSHP installation. If you can provide more data about your house construction, finished or unfinished basement, what was originally conditioned space and square footages, sharp folks (not necessarily me, but I'm a interested novice) on this forum would be better able to help ensure you're moving in the right direction. As you've indicated, you don't want to experience an overuse of heat strips with a GSHP, so getting the heat/cool loads right will prevent that. Dave
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joe.ami
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Posts:1419
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| 03/18/2009 7:47 AM |
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If you would be willing to send me plans or the contractor's complete heat loss work-ups, we can double check this for you.
If you'd like to do that, send me a private message with your contact information.
J |
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Just a Mechanic;
Geothermal; Savings Underfoot |
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heimdm
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New Member
Posts:39
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| 03/19/2009 10:29 PM |
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The walls are built with 2x4 studs. The first floor is 3600 square feet and the basement is right around 1800. The basement walls are concrete block. There is crawlspace all around the basement. The basement was added after the home was built. We were able to heat the house on the strip heaters alone. At max we would have 20k strip heaters (20 x 3413) = 68,260. Based on that I would hope that our heat load would be around 50,000 to 70,000.
Attic Insultation is around R-35.
Contact Info: heimdm@gmail.com
Main Floor
Dimensions - Rectangle Ranch. Living area 90ft by 40ft
Master Bed Room: - 2 glass doors each glass pane measuring 26in x 62in (west)
Master Bath: - 2 windows each mesuring 30in x 42in (1 west, 1 south)
Bedroom 2: 2 windows each measuring 30in x 54in (east)
Bedroom 3: 2 windows each measuring 30in x 54in (east)
Bedroom 4: 2 windows each measuring 30in x 54in (east)
Office: 2 glass doors each glass pane measuring 26in x 62in (west)
Living Room: 2 glass doors each glass pane masuring 26in by 62 in and 2 windows each measuring 30in x 54in (west)
Family Room: 2 windows each measuring 30in x 54in (west)
Kitchen: 2 glass doors each glass pane measuring 26in x 62in + 8 glass panes measuring 19in by 26in (west)
Laundry Room: 2 glass panes measuring 18in x 19in (west)
Mud Room: 2 windows each measuring 30in by 54in (east)
Front door: glass pane 47in by 21 in. (east)
Basement:
Dimensions: 75ft by 24ft. It is concrete block all the way around. |
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joe.ami
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Posts:1419
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| 03/20/2009 8:07 AM |
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| This information is not quite complete enough to help, check your private messages for details and be sure to include contact info. |
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Just a Mechanic;
Geothermal; Savings Underfoot |
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joe.ami
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Posts:1419
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| 03/23/2009 9:01 AM |
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Info provided continues to confuse the issue. I performed an abbreviated load on the house based on info sent to me and found a lower loss, a higher gain and 4 ton providing 91% of reqirement at best.
J |
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Just a Mechanic;
Geothermal; Savings Underfoot |
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joe.ami
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Veteran Member
Posts:1419
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| 03/23/2009 9:26 AM |
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I noticed that the delta t used by the local contractor was 5* different than mine and after changing it found that we agreed on the 94% heat served. I still can't digest the extremely high heat load. Mine was only about 70% of that which is more than the little disparity that I would normally attribute to incomplete data. Cooling loads were within 10% so I'm guessing it is a basement or crawl insulation difference.
I also don't know why it is necessary to replace all the duct work.
J |
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Just a Mechanic;
Geothermal; Savings Underfoot |
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heimdm
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New Member
Posts:39
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| 03/23/2009 10:43 AM |
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Ceiling height is about 9 to 9.5ft.
We have a partial basement that is about 1800 square feet. The top floor is 3600 ft. The non-basement area is crawlspace. The duct work is being replaced because it is virtually 100% flexible duct and is based on the current furance location which is at 1 end of the house. The new location is in the middle of the house, and we are changing the zones from 3 upstairs, to bedroom on zone 1, common areas (living room, family room, kitchen) zone 2, and the basement on zone 3. |
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heimdm
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Posts:39
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| 03/24/2009 9:43 AM |
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So it looks realisitically that my heat load is closer to around 80k btu after the wonderful feedback from everyone. Thank you.
Since we live in the woods and have access to a virtually unlimited supply of wood... only limited by my time to cut it and let it dry out... we are thinking of eventually adding a wood stove/furance. The intention would be on those cold day in Jan/Feb, to use the wood heat to assist the geo instead of having to use resistance.
What consideration need to be made for using wood as a backup to the geo... I am looking at installation and configuration concerns..
Thanks, |
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heimdm
Registered Users
New Member
Posts:39
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| 03/25/2009 8:30 PM |
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I met with my geo guy today and we finalized the design. The geo unit will be a tranquility 27 064 model. I believe the 064 is a 5.5 ton unit. Additionally, the the loop will come off the house is run in 2x 2in tubes to get to the loop field. The loop-field is about 100 feet away from the house. Once at the loop field each of the two feeds will break off into 6 line pipe. Each loop will be 300 feet. That makes 2x 300ft/loops x 6 pipe.
The geo guy said the 100 feet of header plus our very moist soil should add another 1 to 1.5 tons of capacity to the loop. |
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joe.ami
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Posts:1419
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| 03/31/2009 9:49 AM |
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Sounds like a good fit for you. Duct work is the key now, you should have 384 sq" of return air (or so for this system).
J |
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Just a Mechanic;
Geothermal; Savings Underfoot |
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Tomnichols
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Posts:1
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| 04/04/2009 9:14 AM |
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Joe, Hello I was a lead tech @ the largest geothermal company in the midwest. I then started my own company. I live in Indianapolis and would be willing to help you out. Feel free to contact me I have worked with a lot of climate dry systems. I also use geodesigner If you would like any info on geothermal you can get answers from https://WWW.Indygeothermalpros.com or feel free to ask me any questions. Thank You
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joe.ami
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Veteran Member
Posts:1419
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| 04/04/2009 9:39 AM |
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Tom,
Welcome to the forum. The threads autho, heimdm, has since made his purchase.
We'll look forward to your advice on other questions.
Joe |
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Just a Mechanic;
Geothermal; Savings Underfoot |
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shornick
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New Member
Posts:1
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| 07/10/2009 1:16 PM |
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| We just had a Tranquility 27 system installed. It is a 3 ton system with 2 zones set up. We opted for the Climadry as well since we prefer to not use ac much and live in the woods where the humidity levels sometimes rise up.
They have not been able to get this system working for more then a few days at a time. They are using a zone board to split the zones and are now telling us they might not be able to run a climadry system over two zones? Little late now. They only turned the option on the bottom zone t-stat so that the zones wouldn't fight. They seem to think it is backfeeding through the board and frying transformers. Seems odd, I'm pretty sure they we are not the only ones who have wanted this set up. Suggestions and help greatly appreciated. |
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Masoud
Registered Users
Basic Member
Posts:116
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| 07/10/2009 3:44 PM |
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shornick,
I'm not a HVAC pro and I am not giving advice. I am not familiar with your zones. I have ClimaDry and read about it. I share my thoughts.
Units with ClimaDry are more sensitive to air flow restrictions.
The reheat coil should have been purged and air bled from the valve on the top of the reheat coil.
Climatemaster's All Products Technical Guide: 2006-2007, Part 2 DXM Controls, Page 19, in a note indicates: For units with ClimaDry DIP 1.5 should be in the ON position and DIP 2.7 should be in the OFF position. Facing the DXM board, the first set of DIP switches are on the left, and the second set is on the right. I am not aware if this info has been revised. Power to the Tranquility 27 should be turned off when changing DIP switch settings.
Regards,
Masoud |
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